Java：iBatis简单入门

简介:

jar包

普通的javaBean: domain.User

与bean对应的SQL映射文件: maps/User.xml

iBatis需要的配置文件: SqlMapConfig.xml

加载iBatis配置文件SqlMapConfig.xml是相对于class loader所在目录的相对路径. 如在Web程序中，例如Tomcat下时，class loader所对应的目录是WEB-INF/classes目录. 如在普通的单机运用程序中，class loader对应的目录是编译生成class的bin目录(把src和bin分开存放时).

1. 需要的jar包(暂且先用下面的，可到http://www.javaeye.com/topic/26433示例中一起下载):

commons-dbcp.jar, commons-logging-api.jar, commons-logging.jar, commons-pool.jar,

hsqldb.jar, ibatis-common-2.jar, ibatis-dao-2.jar, ibatis-sqlmap-2.jar,

mysql-connector-java-3.1.12-bin.jar

2. 类User:

package domain;

public class User {

private int id;

private String name;

public User() {}

public User(String name) { this(0, name); }

public User(int id, String name) {

this.id = id;

this.name = name;

}

public int getId() { return id; }

public void setId(int id) { this.id = id; }

public String getName() { return name; }

public void setName(String name) { this.name = name; }

@Override

public String toString() { return "ID: " + id + ", Name: " + name; }

}

3. User.xml映射文件:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE sqlMap PUBLIC

"-//iBATIS.com//DTD SQL Map 2.0//EN"

"http://www.ibatis.com/dtd/sql-map-2.dtd">

<sqlMap namespace="User">

<!-- 设置本映射中的别名: 方便使用 -->

<typeAlias alias="user" type="domain.User" />

<typeAlias alias="string" type="java.lang.String" />

<typeAlias alias="integer" type="java.lang.Integer" />

<!-- 增删查改的Statement配置 -->

<select id="getAllUsers" resultClass="user"><![CDATA[

SELECT id, name FROM user ORDER BY id

]]></select>

<select id="getUser" resultClass="user" parameterClass="integer"><![CDATA[

SELECT id, name FROM user WHERE id=#id#

]]></select>

<update id="updateUser" parameterClass="user"><![CDATA[

UPDATE user SET name=#name# WHERE id=#id#

]]></update>

<insert id="insertUser" parameterClass="user"><![CDATA[

INSERT INTO user (name) VALUES (#name#)

]]></insert>

<delete id="deleteUser" parameterClass="integer"><![CDATA[

DELETE FROM user WHERE id=#id#

]]></delete>

</sqlMap>

4. iBatis需要的配置文件:

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE sqlMapConfig

PUBLIC "-//iBATIS.com//DTD SQL Map Config 2.0//EN"

"http://www.ibatis.com/dtd/sql-map-config-2.dtd">

<sqlMapConfig>

<settings cacheModelsEnabled="true" enhancementEnabled="true"

lazyLoadingEnabled="true" errorTracingEnabled="true" maxRequests="32"

maxSessions="10" maxTransactions="5" useStatementNamespaces="false" />

<transactionManager type="JDBC">

<dataSource type="SIMPLE">

<!-- JDBC连接需要的配置 -->

<property name="JDBC.Driver" value="com.mysql.jdbc.Driver" />

<property name="JDBC.ConnectionURL"

value="jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8" />

<property name="JDBC.Username" value="root" />

<property name="JDBC.Password" value="" />

<!-- 连接池配置 -->

<property name="Pool.MaximumActiveConnections" value="10" />

<property name="Pool.MaximumIdleConnections" value="5" />

<property name="Pool.MaximumCheckoutTime" value="120000" />

<property name="Pool.TimeToWait" value="500" />

<property name="Pool.PingQuery" value="select 1 from sample" />

<property name="Pool.PingEnabled" value="false" />

<property name="Pool.PingConnectionsOlderThan" value="1" />

<property name="Pool.PingConnectionsNotUsedFor" value="1" />

</dataSource>

</transactionManager>

<!-- 映射文件 -->

<sqlMap resource="maps/User.xml" />

</sqlMapConfig>

5. 使用iBatis访问数据库:

package test;

import java.io.IOException;

import java.io.Reader;

import java.util.List;

import com.ibatis.common.resources.Resources;

import com.ibatis.sqlmap.client.SqlMapClient;

import com.ibatis.sqlmap.client.SqlMapClientBuilder;

import domain.User;

public class Test {

public static enum Mode {

INSERT, UPDATE, DELETE

}

public void update(Object arg, Mode mode) {

SqlMapClient smc = null;

try {

smc = getSqlMapClient();

smc.startTransaction();

switch (mode) {

case INSERT: smc.insert("insertUser", arg); break;

case UPDATE: smc.update("updateUser", arg); break;

case DELETE: smc.delete("deleteUser", arg); break;

}

smc.commitTransaction();

} catch (Exception e) {

e.printStackTrace();

} finally {

endTransaction(smc);

}

}

public void listUsers() {

SqlMapClient smc = null;

try {

smc = getSqlMapClient();

smc.startTransaction();

List users = smc.queryForList("getAllUsers", null);

System.out.println(users);

smc.commitTransaction();

} catch (Exception e) {

e.printStackTrace();

} finally {

endTransaction(smc);

}

}

public User selectUser(int id) {

User user = null;

SqlMapClient smc = null;

try {

smc = getSqlMapClient();

smc.startTransaction();

user = (User) smc.queryForObject("getUser", id);

smc.commitTransaction();

} catch (Exception e) {

e.printStackTrace();

} finally {

endTransaction(smc);

}

return user;

}

// ////////////////////////////////////////////////////////////////////////

// Don't care

// ////////////////////////////////////////////////////////////////////////

private SqlMapClient getSqlMapClient() throws IOException {

// 初始化ibatis, 获得一个SqlMapClient对象

String resource = "SqlMapConfig.xml";

Reader reader = Resources.getResourceAsReader(resource);

return SqlMapClientBuilder.buildSqlMapClient(reader);

}

private void endTransaction(SqlMapClient smc) {

if (smc == null) { return; }

try {

smc.endTransaction();

} catch (Exception e2) {

e2.printStackTrace();

}

}

public static void main(String[] args) {

Test t = new Test();

t.listUsers();

User user = new User("Biao");

user = t.selectUser(7);

user.setName("Biao 黄河");

t.update(user, Mode.UPDATE);

// t.update(user, Mode.INSERT);

// t.update(Integer.valueOf(7), Mode.DELETE);

t.listUsers();

}

}